Invalid Packet Size

zappu

Dear users,

I have an issue, I have at home a Zywall USG100-PLUS and I'm trying to connect via SSL VPN, with SecuExtender, but is not working. Every time I receive this error: SSL tunnel receives a packet with invalid packet size.

Can someone help me with this issue ?

Thank you

Kind regards,

Alex

PeterUK

Are you using the newest SecuExtender and firmware 3.30(AACV.7)C0 ?

Maybe try changing your MTU

Or set your NIC to disable jumbo frame.

zappu

Hello Peter,

Sorry for my late reply. As a Firmware Package it shows me these:

Boot module: 1.17

Current version: V3.30(AACV.6)

Do I need to have 3.30 (AACV.7) ? As for SecuExtender, yes I have the latest for SSL VPN.

The part of MTU or NIC where I can find it ?

Thank you

Regards,

Alex

PeterUK

In windows try this in CMD run as admin

netsh interface ipv4 set interface "Local Area Connection" mtu=1492

check here that its done

https://www.speedguide.net/analyzer.php

if you run SecuExtender in your LAN to USG100-PLUS does it connect fine?

Zyxel_Cooldia

Hi @zappu

Welcome to Zyxel Community. ?

The SeueExtender establish tunnel via virtual NIC ”Tap-Windows Adapter V9 for Zyxel SecuExtender”.

Can you post your MTU value on that virtual NIC?

Control panel > Network and Internet Connection > Network connection 

click “configure ” to see the MTU value.

zappu

Dear guys,

Here is the picture from my friend and it seems, it doesn't work also with modifications.

computer.png

Zyxel_Cooldia

Hi @zappu ,

Can you send me your configuration file via private message. 

Let me have a quick lab test with your configuration file.

zappu

Hi @Zyxel_Cooldia,

I sent you via private message the both files that I have in my router.

Anyway yesterday night when I test it, I mean 1st I modified in my router on WAN from 1500 to 1400 and my Internet goes down and then I put it back to 1500. As for LAN when I modified from 1500 to 1400, 1392, 1370, 1300 or 1000, it works to connect to my LAN, but after 18 seconds he disconnected automatically and on my logs I received same error as the 1st one that I have put in my 1st message.

I hope you can help me with this issue :).

Thank you

Regards,

Alex

Zyxel_Cooldia

Hi @zappu ,

As I remote check, the settings is good, and the tunnel uptime is around 20 minutes after I establish SSL VPN tunnel. Can you try to connect SecuExtender again with other pc?

zappu

Dear Chen,

I made the tests and it seems is not working.

Please find attached the pictures from my friend and also from my router.

What we can do ??

Thank you

Regards,

Alex

vpn.PNG

zyxel-vpn-ssl.PNG

Zyxel_Cooldia

Hi @zappu ,

It may need to remote check on your SecuExtender client, I will contact you via private message.